Accelerating the vulcanization of rubber and method of producing the same



Patented Jan. 30, 1923.

UNITED STATES teaser STANLEY JOHN PEACHEY, OF DAVENPORT, STOCKPOBT, ENGLAND.

Acc'eLEaArme THE VULCANIZATION or RUBBER AND METHOD or raonncme THE SAME. v i

No Drawing To (all whom it may concern:

Be it known that I, STANLEY JOHN PEAoHnY, a subject of the King of Great Britain and Ireland, and resident of Daventain new and useful Improvements in New Agents for Accelerating the Vulcalnzation of Rubber and Methods of Producing the.

Same, of which the following is a specification.

This invention refers to and consists of (1) new agents for accelerating the vulcanization of rubber or rubber-like substances by sulphur. (2) a method of producing such agents, and (3) the use of such agents in the vulcanization of rubber by sulphur.

According to the invention, the new agents are produced by subjecting a mixture of paranitroso dilnethylaniline and sulphur to heat, which causes awigorous reaction resulting in two products being obtained, either of which on being added to rubber prior to vulcanization will serve to accelerate the vulcanization.

In carrying out the invention, the paranitroso. dimethylaniline is mixed with sulphur in quantities corresponding to one molecular proportion, of paranitroso dimethylaniline and from one to two atomic proportions of sulphur, or inproportions differing from these according to the physical nature and condition which the product, or one of the products, is desired to possess, for example, a considerable excess of sulphur may be employed in order to obtain a product containing free sulphur and one which will readily grind to powder, or less sulphur may be employed, when a more resinous product is obtained, which may contain free paranitroso dimethylaniline. The ultimate products possess accelerating action due to the presencecf the new, agent or age ts. The mixture of the paranitroso diinethylaniline and sulphur in the proportions stated is heated to a temperature of about 130'135 (1., or thereabouts, whereupon a vigorous reaction takes place resulting in the evolution of dense reddish colcured fumes, which condense on cooling to a yellowish red substance. The residual substance left after the reaction has completed itself is a dark brown resinous substance, soluble in a number of organic solvents. Both the yellowish red condensate Application filed July 15, 1918. Serial No. 245,097.-

and the residual brown resin act as powerful accelerators of the vulcanizing process when a small quantity of either 15 added to a rubber prior to heating. 5 port, Stockport, England. have invented cer- As an alternative to the above process, sulphur (preferably in considerable excess of the amount corresponding to one atomic proportion to one molecular proportion of paranitroso dimethylaniline) is melted in a Suita le vessel, heated to the reacting temperature, and the paranitroso dimethylaniline is added in small portions at a time with stirring. As soon as the vigorous reaction produced by such addition subsides, a fresh portion is added and so on until the whole of the nitroso compound has been introduced.

By using the sulphur in considerable excess of'the amount required for the reaction. a residual product is obtained which presents the appearance of a hard dark coloured resin which is readily reduced to a fine powder. 4,

Using an openatssel for the above operation the red furn'es't re of course dispersed,

ing but the product then contains appreci-able amounts of free paranitroso dimethylaniline, which .is undesirable in that this free nitroso base possesses objectionable staining properties, whereas one of the objects of this invention is to provide a product which is free from unchanged para nitroso dimethylaniline and therefore does not stain.

' The following examples serve to illustrate the processes referred to above, but I do not confine myself to the proportions stated as these may be varied considerably without departing from the invention.

Example 1: 15 parts by weight of par-anitroso dimethylaniline are intimately mixed with 5 parts by weight of powdered sulphur-and'the mixture isvheated in a flask with a side tube leading into a condenser and receiver. As soon as the temperature reaches 130-l35 0., or tbereabouts, a vigorous reaction takes lace with the evolution of reddish coloured fumes, which partly condense in the condenser andreceiver, forming a yelescape and are lost (although means may bev devised for condensation if desired). The residual productforn1s,on cooling, a hard brittle resin, which powders easily and forms a useful accelerator of vulcanization.

, In applying the new agents as accelerators 1 the vulcanizing process, the procedure 18 to add either of the new agents in appropriate quantity to the rubber mixing" prior to-vnlcanization, and then to heat the mixing to the i'ulcanizing temperature by any of the well known methods, when a well vulcanized rubber is obtained in tar'shorter time than the case when the accelerating agent is absent.

desired, allowance may be made for any tree sulphur present in the accelerator and this may be deducted from the amount of sulphur added to the mixing.

As exam ales of re nations the followin 2* are given, but I do not confine myself to the proportions specified as variations may be made therein without departing from the invention. I

- 100 parts by weight of plantation rubber.

10 parts by weight of sulphur.

0.5 parts of either of the. products obtained according to the direction previously gigen in 1.

l he mining, is heated to a temperature corresponding to a steam pressure of from 40.

to 45 lbs. when perfect vulcanization is obtained in about to minutes, a much shorter period than is required in the ordinary way, that is, Without the additionor' the accelerating. agent.

- 1.00 parts by weight of para rubber.

10 parts by weight of sulphur.

l to 1.5 parts by weightof the residual product obtained according to the directions given in Example 2.

The mixing heated to a temperature corresponding to a steam pressure of from 40 to lbs, when vulcanization is completed in 30 to 40 minutes, a much shorter period than is required in the absence of the accelerator.

10!) parts'by weight of plantation rubber.

4.0 parts by weight of sulphur.

2 parts by Weight of the residual product obtained according to the directions "given in Example 2.

The mixing is heated for 2 to 3 hours at a temperature corresponding to a steam pressure of 4:0 to lbs, and a durable hard rubber is thus obtained in about one-third to one-half of the time normally required.

In my former Patent No. 1,157,177 paranitroso dimethylaniline was used directly as an accelerator oi the vulcanizing process In my present invention the paran'itro so diriiethylaniline is not so used, but is previously converted by heating with sulphur into a new compoundor compounds, possessing accelerating properties, and also possessing the important advantage that, unlike paranitroso dimethylaniline, it or they are free from objectionable stainingproperties. lVhat I claim is:-'

'1. A process or method of producing new agents for accelerating the vulcanization of rubber or rubber-like substances, consisting inheating together paranitroso-dimethylaniline and sulphur to a temperature atwhiich interaction takes place, recovering the react-ion residue and condensin the vapours formed to constitute accelerating agents, substantially as described.

2. A process or method of producing new agents for accelerating the vulcanization of rubber or rubber-like substances, consisting in heating together paranitroso diulethylaniline and sulphur to a temperature of approximately l30-135 (1., recoveringthe reaction residue and condensing the vapours formed to constitute acccelerating agents, substantially described.

3. A process or method of producing new agents for accelerating the vulcanization of rubber or rubber-like substances, consisting in heating together paranitroso-dimethylaniline and sulphur in quantities approximating to one molecular proportion or paranitroso diimethylaniline and two atomic proportions of sulphur, recovering the reaction residue and condensing the vapours formed to constitute accelerating agents, sul'istantially as described.

4. A process or method of producing new agents for accelerating the vulcanization of rubber or rubber-like in heating together aniline and sulphur in quantities approximating to one molecular proportion of para nitroso-dimethylaniline and two atomic proportions of sulphur to. a temperature or approximately 13()135 (3., recovering the reaction rcsidlle and condensing the vapours formed to constitute accelerating agents, substantially as described.

Materials or agents for accelerating the vulcanization of rubber or rubber-like substances consisting of the condensate prosubstances, consisting 1 paranitroso-dimethylthe vulcanization (if rubber or duced by heating together paranitroso-dimetl' vlanilinc andsulphur to a temperature at WW ich interaction takes place, substant ially as described.

6. Materials or agents for accelerating the vulcanization of rubber or rubber-like substances consisting of the condensate produced by heating together paranitroso-dimethylaniline to a temperature of approximately l30l35 C., substantially as de scribed.

7. Materials or agents for accelerating the vulcanization of rubber or rubber-like substances consisting of the condensate produced by heating together paranitroso-dimetbylaniline and sulphur in quantities approximating to one molecular proportion of paranitroso dimetlrvlaniline and two atomic proportions of sulphur, substantially as described. l

8. Materials or agents for accelerating rubber-like substances-consisting of the condensate pro duced by heating together paranitroso-dimethylaniline and. sulphur in quantities approxlmating to one molecular proportion of paranitroso dimethylaniline and two atomic proportions of sulphur to a temperature of approximately 130?135 (1., substantially as described.

9. Materials or agents for accelerating the vulcanization of rubber or rubber-like substances consisting of the non-volatile residue produced. b heating together paranitrosodimethylttniline and sulphur to 'a temperature at which interact-ion takes place, substantia y as described.

l0. Ilaterials or agents'for accelerating the \"dcanization of rubber or rubber-like substances consisting of the non-volatile residue produced by heating together paranitroso-dimethylaniline to a temperature of approximatel 130135 substantially as described.

11. Materials or agents for accelerating the vulcanization of rubber or rubberlike substances consisting of the non-volatile residue produced by heating together paranitrosodimethylaniline and sulphurin quantities up proximating to one molecular proportion of paranitroso dimethylaniline and two atomic proportions of sulphur substantially as described.

12. Materials or agents for accelerating the vulcanization of rubber or rubber-like substances consisting of the non'-volatile residue produced by heating together paranitroso dimetlrvlaniline and sulphur in quantities approximating to one molecular proportion of paranitroso dimethylaniline and two atomic proportions of sulphur to a temperature of approximately 130 -135 (7., substantially as herein described.

In witness whereof I have hereunto set my hand in the presence of two witnesses.

STA NLIG Y J ()H N PEACH E Y.

\Vitnesses HENRY JUNoA,

. 7 JoHN ll ILLIAM FHOMAS. 

